Treatment Solution for Ink-Jet Recording, Water-Based Ink Set for Ink-Jet Recording, Ink-Jet Recording Method and Ink-Jet Recording Apparatus

ABSTRACT

A treatment solution for ink-jet recording includes water; and basic amino acid or a salt thereof which is contained in the treatment solution in an amount of not less than 1% by weight.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2011-052281 filed on Mar. 10, 2011 the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a treatment solution for ink-jetrecording, a water-based ink set for ink-jet recording, an ink-jetrecording method and an ink-jet recording apparatus.

2. Description of the Related Art

In some cases, before or after ink jet recording with a water-based ink,a treatment solution in which polyallylamine, polyvalent metal ion, etc.is/are blended is used, for the purpose of improving optical density (ODvalue) of a recorded matter (recorded item) with the water-based ink.The polyallylamine, polyvalent metal ion, etc. contained in thetreatment solution are capable of causing a colorant in the water-basedink to aggregate on a recording medium, consequently making it possibleto improve the optical density (OD value) of the recorded matter.

However, with the treatment solution in which the polyallylamine and thepolyvalent metal ion, etc. are blended, only the optical density (ODvalue) of the recorded matter is improved. On the other hand, thetreatment solution is also required to have a property such as theresisting property against highlighter-pen (highlighter-resistingproperty) and storage stability. However, no conventional treatmentsolutions are excellent in all the properties that are the opticaldensity (OD value) of the recorded matter, the highlighter-resistingproperty, and storage stability.

In view of the above situation, an object of the present invention is toprovide a treatment solution for ink-jet recording which is excellent inall the properties that are the optical density (OD value) of therecorded matter, the highlighter-resisting property and the storagestability.

SUMMARY OF THE INVENTION

According to a first aspect of the present teaching, there is provided atreatment solution for ink-jet recording, including: water; and basicamino acid or a salt thereof which is contained in the treatmentsolution in an amount of not less than 1% by weight.

According to a second aspect of the present teaching, there is provideda water-based ink set for ink-jet recording, including: a water-basedink for ink-jet recording containing a colorant, water and awater-soluble organic solvent; and the treatment solution of the firstaspect.

According to a third aspect of the present teaching, there is providedan ink jet recording method for performing recording on a recordingmedium, the method including: applying, to the recording medium, thetreatment solution of the water-based ink set for ink-jet recording ofthe second aspect; and discharging, to the recording medium, thewater-based ink of the water-based ink set for ink-jet recording.

According to a fourth aspect of the present teaching, there is providedan ink-jet recording apparatus which performs recording on a recordingmedium, the apparatus including: an ink-set accommodating section whichaccommodates the water-based ink set for ink-jet recording of the secondaspect therein; a treatment solution applying mechanism which applies,to the recording medium, the treatment solution of the water-based inkset for ink-jet recording; and an ink discharge mechanism whichdischarges, to the recording medium, the water-based ink of thewater-based ink set.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of construction of an example ofan ink-jet recording apparatus of the present teaching.

FIGS. 2A and 2B are images for illustrating examples of recording withan ink-jet recording method of the present teaching.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present teaching, the term “highlighter-resisting property” meansa property or state that when, for example, a text portion, recordedwith a water-based ink, is traced with a highlighter-pen or highlighterhaving a fluorescent color, there is no flowing out of the ink from thetext, there is no blurring in the text and the tip of the highlighter isnot dirtied.

As described above, the treatment solution of the present teaching is atreatment solution used for ink-jet recording and including: basic aminoacid; and water. The treatment solution of the present teaching mayinclude a component different from the basic amino acid and the water.

The blending amount of the basic amino acid is not less than 1% byweight with respect to the total amount of the treatment solution. It ispresumed that when the treatment solution and the water-based ink arebrought into contact with each other on the recording medium, the basicamino acid causes the colorant in the water-based ink to aggregate; andby making the blending amount of the basic amino acid to be not lessthan 1% by weight, it is possible to improve the optical density of therecorded matter. Further, by blending the basic amino acid in thetreatment solution be not less than 1% by weight, it is possible toobtain a treatment solution not only having an increased optical density(OD value) of the recorded matter, but also excellent in thehighlighter-resisting property and the storage stability. The term“storage stability” herein mainly means that a color of the treatmentsolution is not changed (yellowed) after a storage test (the treatmentsolution does not undergo color-change after a storage test). Since thetreatment solution of the present teaching is excellent in the storagestability and hardly undergoes color-change (yellowed), the treatmentsolution would not affect the color of the recorded matter. The blendingamount of the basic amino acid is preferably not less than 2% by weight.The upper limit value of the blending amount of the basic amino acid isnot particularly limited, and the blending amount is, for example, notmore than 10% by weight and is preferably not more than 7% by weight.

The basic amino acid is exemplified by a compound represented by thefollowing general formula (I):

in the general formula (I), “R” is a basic functional group having afunctional group containing a nitrogen atom at terminal thereof.Specific examples of the basic amino acid include lysine, arginine,histidine, ornithine, hydroxylysine, tryptophan, desmosine, creatine,γ-aminobutyric acid, etc. among which lysine, arginene, histidine,ornithine are preferable.

The basic amino acid may include a derivative of the basic amino acid.In a case that an isomer such as a tautomer or steroisomer (for example,geometric isomer, conformational isomer and steroisomer), etc. exists inthe basic amino acid and the derivative thereof, it is allowable to useany one of the isomers in the present teaching. Further, salt of thebasic amino acid and salt of the derivative of the basic amino acid mayalso be used in the present teaching. The salt is exemplified by acidaddition salt. The acid composing the acid addition salt may be aninorganic acid or organic acid. Although the inorganic acid is notparticularly limited, the inorganic acid is exemplified by hydrochloricacid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromicacid, hydroiodic acid, hypofluorous acid, hypochlorous acid, hypobromousacid, hypoiodous acid, fluorous acid, chlorous acid, bromous acid,iodous acid, fluoric acid, chloric acid, bromic acid, iodic acid,perfluorinated acid, perchloric acid, perbromic acid, periodic acid,etc. Although the organic acid is also not particularly limited, theorganic acid is exemplified by glutamic acid, p-toluenesulfonic acid,methanesulfonic acid, oxalic acid, p-bromobenzenesulfonic acid, carbonicacid, succinic acid, citric acid, benzoic acid, acetic acid, hydroxycarboxylic acid, propionic acid, malonic acid, adipic acid, fumaricacid, maleic acid, etc.

The water which is used in the treatment solution is preferablyion-exchanged water or pure water (purified water). The blending amountof water with respect to the total amount (entire amount) of thetreatment solution is, for example, the balance of the treatmentsolution, excluding the other component(s).

The treatment solution may further include a water-soluble organicsolvent. As the water-soluble organic solvent, it is allowable to usepublicly or conventionally known products or substances. Thewater-soluble organic solvent include, for example, polyvalent(polyhydric) alcohol, polyvalent alcohol derivative, alcohol, amide,ketone, ketoalcohol (ketone alcohol), ether, nitrogen-containingsolvent, sulfur-containing solvent, propylene carbonate, ethylenecarbonate, 1,3-dimethyl-2-imidazolidinone, etc. The polyvalent alcoholincludes, for example, glycerol, ethylene glycol, propylene glycol,butylene glycol, hexylene glycol, diethylene glycol, triethylene glycol,polyethylene glycol, dipropylene glycol, tripropylene glycol,polypropylene glycol, trimethylolpropane, 1,5-pentanediol,1,2,6-hexanetriol, etc. The polyvalent alcohol derivative includes, forexample, ethylene glycol methyl ether, ethylene glycol ethyl ether,ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether,diethylene glycol methyl ether, diethylene glycol ethyl ether,diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether,diethylene glycol-n-hexyl ether, triethylene glycol methyl ether,triethylene glycol ethyl ether, triethylene glycol-n-propyl ether,triethylene glycol-n-butyl ether, propylene glycol methyl ether,propylene glycol ethyl ether, propylene glycol-n-propyl ether, propyleneglycol-n-butyl ether, dipropylene glycol methyl ether, dipropyleneglycol ethyl ether, dipropylene glycol-n-propyl ether, dipropyleneglycol-n-butyl ether, tripropylene glycol methyl ether, tripropyleneglycol ethyl ether, tripropylene glycol-n-propyl ether, and tripropyleneglycol-n-butyl ether, etc. The alcohol includes, for example, methylalcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butylalcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, benzylalcohol, etc. The amide includes, for example, dimethylformamide,dimethylacetamide, etc. The ketone includes, for example, acetone, etc.The ketone aocohol (ketoalcohol) includes, for example, diacetonealcohol, etc. The ether includes, for example, tetrahydrofuran, dioxane,etc. The nitrogen-containing solvent includes, for example, pyrrolidone,2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone,triethanolamine, etc. The sulfur-containing solvent includes, forexample, thiodiethanol, thiodiglycol, thiodiglycerol, sulfolane,dimethylsulfoxide, etc. The blending amount of the water-soluble organicsolvent with respect to the entire amount of the treatment solution isnot particularly limited. One kind of the water-soluble organic solventmay be used, or two or more kinds of the water-soluble organic solventmay be used together.

It is allowable that the treatment solution contains a colorant, or itis allowable that the treatment solution does not contain any colorant.In a case that the treatment solution contains a colorant, it ispreferable that the colorant is contained in the treatment solution inan amount to an extent not affecting the recording of image and/orletter, etc.

The treatment solution may further contain a conventionally knownadditive, if necessary. The additive includes, for example, surfactants,pH-adjusting agents, viscosity-adjusting agents, surfacetension-adjusting agents, antioxidants, fungicides, etc. Theviscosity-adjusting agents include, for example, polyvinyl alcohol,cellulose, water-soluble resin, etc.

The treatment solution can be prepared, for example, by mixing the basicamino acid and water, and optionally other additive component(s) asnecessary uniformly or homogeneously by any conventionally known method.

Although the pH of the treatment solution is not particularly limited,the pH is, for example, not less than 6 and is preferably not less than6.5.

A water-based ink for ink-jet recording (hereinafter referred to alsosimply as “water-based ink” or “ink”), which is usable together with thetreatment solution of the present teaching, is not particularly limited.For example, it is allowable to use, as the water-based ink, awater-based ink which is to be explained next regarding a water-basedink set for ink jet recording. Further, a water-based ink using apigment in the colorant has a problem associated with thehighlighter-resisting property of the recorded matter in some cases.Therefore, the treatment solution improving the highlighter-resistingproperty is suitable to be used together with the water-based ink usingthe pigment.

The above-described treatment solution for ink jet recording of thepresent teaching is excellent in all of the optical density (OD value)of the recorded matter, the highlighter-resisting property and thestorage stability.

Next, an explanation will be given about a water-based ink set forink-jet recording (hereinafter also referred to simply as “water-basedink set” or “ink set”) of the present teaching. The water-based ink setof the present teaching is a water-based ink set including a water-basedink and a treatment solution for ink-jet recording, wherein thewater-based ink is a water-based ink containing a colorant, water and awater-soluble organic solvent; and the treatment solution is thetreatment solution of the present teaching. The water-based ink set inwhich the water-based ink and the treatment solution of the presentteaching are used in combination is excellent in the optical density (ODvalue) of recorded matter, and excellent in the highlighter-resistingproperty.

The colorant may be any one of a pigment and a dye. Further, a pigmentand a dye may be mixed and used as the colorant. Further, in a case thata pigment is used as the colorant, there arises a problem associatedwith the highlighter-resisting property of the recorded matter in somecases. Therefore, the treatment solution improving thehighlighter-resisting property is suitable to be used together with thewater-based ink using the pigment.

The pigment includes, for example, carbon black, an inorganic pigment,an organic pigment, etc. The carbon black includes, for example, furnaceblack, lamp black, acetylene black, channel black, etc. The inorganicpigment includes, for example, titanium oxide, inorganic pigments basedon iron oxide, and inorganic pigments based on carbon black. The organicpigment includes, for example, azo-pigments such as azo lake, insolubleazo-pigment, condensed azo-pigment, chelate azo-pigment and the like;polycyclic pigments such as phthalocyanine pigment, perylene and perynonpigments, anthraquinone pigment, quinacridone pigment, dioxadinepigment, thioindigo pigment, isoindolinone pigment, quinophthalonepigment and the like; dye lake pigments such as basic dye type lakepigment, acid dye type lake pigment and the like; nitro pigments;nitroso pigments; aniline black daylight fluorescent pigment; and thelike. Any other pigment is also usable provided that the pigment isdispersible in a water phase (aqueous phase). Specific example of thepigments as described above include, for example, C. I. Pigment Blacks1, 6, and 7; C. I. Pigment Yellows 1, 2, 3, 12, 13, 14, 15, 16, 17, 55,78, 150, 151, 154, 180, 185, and 194; C. I. Pigment Oranges 31 and 43;C. I. Pigment Reds 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1,112, 122, 123, 139, 144, 146, 149, 166, 168, 175, 176, 177, 178, 184,185, 190, 202, 221, 222, 224, and 238; C. I. Pigment Violet 196; C. I.Pigment Blues 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22, and 60; C. I.Pigment Greens 7 and 36; and the like.

The pigment may be a self-dispersible pigment. The self-dispersiblepigment is dispersible in water without using any dispersing agent, forexample, owing to the fact that at least one of the hydrophilicfunctional group and the salt thereof including, for example, carbonylgroup, hydroxyl group, carboxylic acid group, sulfonic acid group(sulfonate group), phosphoric acid group (phosphate group), etc. isintroduced into the surfaces of the pigment particles by the chemicalbond directly or with any group intervening therebetween. It is possibleto use self-dispersible pigments subjected to the surface treatment byany one of methods described, for example, in Japanese PatentApplication Laid-open No. 8-3498 and Published Japanese Translation ofPCT International Publication for Patent Application No. 2000-513396,Published Japanese Translation of PCT International Publication forPatent Application No. 2008-524400, Published Japanese Translation ofPCT International Publication for Patent Application No. 2009-515007,etc. It is possible to use, as a material for the self-dispersiblepigment, either one of the inorganic pigment and the organic pigment.Further, a pigment which is suitable for the above-described treatmentincludes for example carbon black such as “MA8” and “MA100” produced byMitsubishi Chemical Corporation and “Color Black FW200” produced byDegussa. As the self-dispersible pigment, it is possible, for example,to use a commercially available product. The commercially availableproduct includes, for example, “CAB-O-JET (trade name) 200”, “CAB-O-JET(trade name) 250C”, “CAB-O-JET (trade name) 260M”, “CAB-O-JET (tradename) 270Y”, “CAB-O-JET (trade name) 300”, “CAB-O-JET (trade name) 400”,“CAB-O-JET (trade name) 450C”, “CAB-O-JET (trade name) 465M” and“CAB-O-JET (trade name) 470Y” produced by Cabot Specialty Chemicals;“BONJET (trade name) BLACK CW-2” and “BONJET (trade name) BLACK CW-3”produced by Orient Chemical Industries, Ltd.; “LIOJET (trade name) WDBLACK 002C” produced by Toyo Ink Mfg. Co., Ltd.; and the like.

The solid content blending amount of the pigment (pigment solid content)with respect to the entire amount of the water-based ink is notparticularly limited, and may be appropriately determined based on, forexample, desired optical density or color (hue, tint), etc. The pigmentsolid content is, for example, 0.1% by weight to 20% by weight, ispreferably 1% by weight to 10% by weight, and is more preferably 2% byweight to 8% by weight.

The dye is not specifically limited, which includes, for example, directdyes, acid dyes, basic dyes, reactive dyes, etc. Specified examples ofthe dye include, for example, C. I. Direct Black, C. I. Direct Blue, C.I. Direct Red, C. I. Direct Yellow, C. I. Direct Orange, C. I. DirectViolet, C. I. Direct Brown, C. I. Direct Green, C. I. Acid Black, C. I.Acid Blue, C. I. Acid Red, C. I. Acid Yellow, C. I. Acid Orange, C. I.Acid Violet, C. I. Basic Black, C. I. Basic Blue, C. I. Basic Red, C. I.Basic Violet, and C. I. Food Black. C. I. Direct Black includes, forexample, C. I. Direct Blacks 17, 19, 32, 51, 71, 108, 146, 154, and 168.C. I. Direct Blue includes, for example, C. I. Direct Blues 6, 22, 25,71, 86, 90, 106, and 199. C. I. Direct Red includes, for example, C. I.Direct Reds 1, 4, 17, 28, 83, and 227. C. I. Direct Yellow includes, forexample, C. I. Direct Yellows 12, 24, 26, 86, 98, 132, 142, and 173. C.I. Direct Orange includes, for example, C. I. Direct Oranges 34, 39, 44,46, and 60. C. I. Direct Violet includes, for example, C. I. DirectViolets 47 and 48. C. I. Direct Brown includes, for example, C. I.Direct Brown 109. C. I. Direct Green includes, for example, C. I. DirectGreen 59. C. I. Acid Black includes, for example, C. I. Acid Blacks 2,7, 24, 26, 31, 52, 63, 112, and 118. C. I. Acid Blue includes, forexample, C. I. Acid Blues 9, 22, 40, 59, 93, 102, 104, 117, 120, 167,229, and 234. C. I. Acid Red includes, for example, C. I. Acid Reds 1,6, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 180, 256, 289, 315, and 317.C. I. Acid Yellow includes, for example, C. I. Acid Yellows 11, 17, 23,25, 29, 42, 61, and 71. C. I. Acid Orange includes, for example, C. I.Acid Oranges 7 and 19. C. I. Acid Violet includes, for example, C. I.Acid Violet 49. C. I. Basic Black includes, for example, C. I. BasicBlack 2. C. I. Basic Blue includes, for example, C. I. Basic Blues 1, 3,5, 7, 9, 24, 25, 26, 28, and 29. C. I. Basic Red includes, for example,C. I. Basic Reds 1, 2, 9, 12, 13, 14, and 37. C. I. Basic Violetincludes, for example, C. I. Basic Violets 7, 14, and 27. C. I. FoodBlack includes, for example, C. I. Food Blacks 1 and 2.

The blending amount of the dye (dye ratio) with respect to the entireamount of the water-based ink is not specifically limited, which is, forexample, 0.1% by weight to 20% by weight, preferably 0.3% by weight to10% by weight.

One type of the colorant as described above may be used singly, or twoor more types of the colorants as described above may be used incombination.

The water used in the water-based ink is preferably ion-exchanged wateror pure water (purified water). The blending amount of water (waterratio) with respect to the entire amount of the water-based ink is, forexample, 10% by weight to 90% by weight, and is preferably 40% by weightto 80% by weight. The water ratio may be, for example, the balance ofthe ink, excluding the other components.

The water-soluble organic solvent used in the water-based ink includes,for example, a humectant which prevents the water-based ink from dryingat an end of the nozzle in the ink-jet head and a penetrant whichadjusts the drying speed of the water-based ink on a recording medium.

The humectant is not particularly limited, and includes, for example,lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol,isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butylalcohol; amides such as dimethylformamide and dimethylacetamide; ketonessuch as acetone; ketoalcohols (ketone alcohols) such as diacetonealcohol; ethers such as tetrahydrofuran and dioxane; polyvalent(polyhydric) alcohols such as polyalkylene glycol, alkylene glycol, andglycerol; 2-pyrrolidone; N-methyl-2-pyrrolidone; and1,3-dimethyl-2-imidazolidinone. The polyalkylene glycol is not limited,and includes, for example, polyethylene glycol and polypropylene glycol.The alkylene glycol is not limited, and includes, for example, ethyleneglycol, propylene glycol, butylene glycol, diethylene glycol,triethylene glycol, dipropylene glycol, tripropylene glycol,thiodiglycol, and hexylene glycol. It is allowable that only one kind ofthe humectant as described above is used, or two or more kinds of thehumectants are used in combination. Among the above-describedhumectants, it is preferable to use polyvalent alcohols such as alkyleneglycol, glycerol, etc.

The blending amount of the humectant with respect to the entire amountof the water-based ink is, for example, 0% by weight to 95% by weight,is preferably 5% by weight to 80% by weight, and is more preferably 5%by weight to 50% by weight.

The penetrant is not limited, and includes, for example, glycol ether.The glycol ether is not limited, and includes, for example, ethyleneglycol methyl ether, ethylene glycol ethyl ether, ethyleneglycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycolethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butylether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether,triethylene glycol ethyl ether, triethylene glycol-n-propyl ether,triethylene glycol-n-butyl ether, propylene glycol methyl ether,propylene glycol ethyl ether, propylene glycol-n-propyl ether, propyleneglycol-n-butyl ether, dipropylene glycol methyl ether, dipropyleneglycol ethyl ether, dipropylene glycol-n-propyl ether, dipropyleneglycol-n-butyl ether, tripropylene glycol methyl ether, tripropyleneglycol ethyl ether, tripropylene glycol-n-propyl ether, and tripropyleneglycol-n-butyl ether. It is allowable that only one kind of thepenetrant as described above is used, or two or more kinds of thepenetrants are used in combination.

The blending amount of the penetrant with respect to the entire amountof the water-based ink is, for example, 0% by weight to 20% by weight,is preferably 0.1% by weight to 15% by weight, and is more preferably0.5% by weight to 10% by weight.

The water-based ink may further contain a conventionally known additive,if necessary. The additive includes, for example, surfactants,pH-adjusting agents, viscosity-adjusting agents, surfacetension-adjusting agents, fungicides, etc. The viscosity-adjustingagents include, for example, polyvinyl alcohol, cellulose, water-solubleresin, etc.

The water-based ink can be prepared, for example, by mixing thecolorant, water, a water-soluble organic solvent, and optionally otheradditive component(s) as necessary uniformly or homogeneously with anyconventionally known method, and by removing undissolved matters by afilter or the like.

Next, in the present teaching, the water-based ink set for ink-jetrecording can be provided also as an ink cartridge. The ink cartridge ofthe present teaching is, for example, an ink cartridge having an inkaccommodating section and a treatment solution accommodating section,wherein the ink accommodating section accommodates the water-based inkof the present teaching and the treatment solution accommodating sectionaccommodates the treatment solution of the present teaching. The inkcartridge of the present teaching may further include an accommodatingsection for another water-based ink other than the water-based ink ofthe present teaching.

The ink cartridge of the present teaching may be an ink cartridgeassembly in which a water-based ink cartridge and a treatment solutioncartridge, which are formed independently (distinctively) from eachother, are assembled or collected; or may be an integrated-type inkcartridge of which an inner space is partitioned to define an inkaccommodating section and a treatment solution accommodating section. Itis allowable to use, for example, a conventionally known body for inkcartridge as the body of the ink cartridge of the present teaching.

Next, explanation will be given about an ink jet recording method and anink-jet recording apparatus of the present teaching.

The ink-jet recording method of the present teaching is an ink-jetrecording method for performing recording on a recording medium by usinga water-based ink set including a water-based ink and a treatmentsolution for ink jet recording, the method including: applying thetreatment solution to the recording medium; and performing recording onthe recording medium by discharging (jetting) the water-based ink by theink jet system (in the ink jet manner) to the recording medium, whereinthe water-based ink set for ink jet recording of the present teaching isused as the water-based ink set.

The ink jet recording apparatus of the present teaching is an ink jetrecording apparatus including: an ink-set accommodating section whichaccommodates the water-based ink set for ink jet recording of thepresent teaching therein; and a treatment solution applying mechanismwhich applies, to a recording medium, the treatment solutionconstructing the water-based ink set for ink jet recording; and an inkdischarge mechanism which discharges, to the recording medium, thewater-based ink constructing the water-based ink set for ink jetrecording.

The ink jet recording method of the present teaching can be carried outby, for example, using the ink jet recording apparatus of the presentteaching. The recording includes printing text (character, letter),printing image or picture, and printing, etc.

As shown in FIG. 1, an ink-jet recording apparatus 1 of the presentteaching includes an ink cartridge assembly 2, an ink dischargemechanism (ink-jet head) 3, a head unit 4, a carriage 5, a driving unit6, a platen roller 7 and a purge device 8 as main constitutivecomponents or parts.

The ink cartridge assembly 2 includes a treatment solution cartridge 2 aand four water-based ink cartridges 2 b. The treatment solutioncartridge 2 a contains the treatment solution of the present teaching.The four water-based ink cartridges 2 b contain four colors ofwater-based inks respectively, the four colors being yellow, magenta,cyan and black.

The ink jet head 3 disposed on the head unit 4 performs recording on arecording medium (for example, recording paper or recording paper sheet)P. The ink cartridge assembly 2 and the head unit 4 are provided orarranged on the carriage 5. The driving unit 6 reciprocates the carriage5 in a linear direction. As the driving unit 6, it is possible to use,for example, a conventionally known driving unit (see, for example,Japanese Patent Application laid-open No. 2008-246821). The platenroller 7 extends in the reciprocating direction of the carriage 5 and isarranged to face or be opposite to the ink-jet head 3.

The purge device 8 sucks or draws unsatisfactory ink (poor ink) whichcontains air bubbles, etc. accumulated or trapped in the ink jet head 3.As the purge device 8, it is possible to use, for example, aconventionally known purge device (for example, see Japanese PatentApplication laid-open No. 2008-246821).

A wiper member 20 is provided on the purge device 8, at a position onthe side of the platen roller 7 such that the wiper member 20 isadjacent to the purge device 8. The wiper member 20 is formed to have aspatula shape, and wipes a nozzle-formed surface of the ink-jet head 3accompanying with the movement (reciprocating movement) of the carriage5. In FIG. 1, a cap 18 is provided to cover a plurality of nozzles ofthe ink-jet head 3 which is returned to a reset position upon completionof the recording, so as to prevent the treatment solution and thewater-based ink from drying.

In the ink jet recording apparatus 1 of the embodiment, the inkcartridge assembly 2 is provided, together with the head unit 4, on onecarriage 5. However, the present teaching is not limited to this. In theink jet recording apparatus, each of the cartridges of the ink cartridgeassembly 2 may be provided on a carriage which is different (separate)from the carriage on which the head unit 4 is provided. Alternatively,each of the cartridges of the ink cartridge assembly 2 may be arrangedand fixed inside the ink jet recording apparatus, rather than beingprovided on the carriage 5. In such aspects, for example, each of thecartridges of the ink cartridge assembly 2 and the head unit 4 which isprovided on the carriage 5 are connected with a tube, etc., and thetreatment solution and the water-based ink are supplied from therespective cartridges of the ink cartridge assembly 2 to the head unit 4via the tubes.

Ink jet recording using the ink-jet recording apparatus 1 is performed,for example, in the following manner. Namely, at first, the treatmentsolution of the present teaching is applied (discharged) to therecording paper sheet P from the ink-jet head 3. The application of thetreatment solution may be performed on an entire surface of a recordingsurface of the recording paper sheet P, or may be performed on a partialportion (a part) of the recording surface. In a case of applying thetreatment solution to a partial portion of the recording surface of therecording paper sheet P (partial application), at least a recordingportion, of the recording surface, on which the recording is performed(is to be performed) with the water-based ink, is an applicationportion. In the case of partial application, the size (dimension) of theapplication portion is preferably greater than that of the recordingportion. For example, in a case that a letter “X” is to be recorded onthe recording paper sheet P, it is preferable that the treatmentsolution is applied so that an application portion 30 is formed with aline width greater than the line width of the letter “X”, as shown inFIG. 2A. Further, in a case that a pattern, an image, etc. is to berecorded on the recording paper sheet P, it is preferable that thetreatment solution is applied so that an application portion 40 isformed to be greater than the pattern, etc., as shown in FIG. 2B.

Next, the water-based ink is discharged from the ink-jet head 3 to theapplication portion, of the recording paper sheet P, on which thetreatment solution has been applied. The time (time interval) from thedischarge of the treatment solution until the discharge of thewater-based ink is not particularly limited. For example, it isallowable to perform the discharge of the water-based ink in a samescanning during which the discharge of the treatment solution is alsoperformed. The treatment solution and the water-based ink are broughtinto contact with each other (make contact with each other) on therecording paper sheet P to thereby improve the optical density (ODvalue) of the recorded image and the highlighter-resisting property.Further, the treatment solution of the present teaching has excellentstorage stability, and hardly undergoes color-change (yellowed), andthus the treatment solution hardly affects the recorded image.

As in this example, it is preferable that the treatment solution is usedas a pre-treatment solution which is applied to the recording papersheet P before the water-based ink is discharged to the recording papersheet P. By doing so, it is possible for example to enhance theaggregation efficiency of the colorant in the water-based ink. Thepresent teaching, however, is not limited to this. In the presentteaching, it is allowable to apply the treatment solution to therecording paper sheet P after the water-based ink has been dischargedfirst to the recording paper sheet P; or it is allowable to perform theapplication of the treatment solution to the recording paper sheet P andthe discharge of the water-based ink to the recording paper sheet P atthe same time.

In the ink jet recording apparatus 1 of the present teaching, the inkdischarge mechanism functions also as the treatment solution applyingmechanism. The present teaching, however, is not limited to this. In thepresent teaching, the application of the treatment solution may beperformed, for example, by a system or method such as stamp coating(application), brush coating, roller coating, etc.

The recording paper sheet P on which the recording has been performed insuch a manner is discharged from the ink-jet recording apparatus 1. InFIG. 1, a paper feeding mechanism and a paper discharging mechanism forthe recording paper sheet P are omitted.

In the apparatus shown in FIG. 1, an ink-jet head of serial type (serialtype ink-jet head) is adopted. However, the present teaching is notlimited to this. The ink jet recording apparatus may be an apparatusadopting an ink-jet head of line type (line type ink jet head).

EXAMPLES

Next, examples of the present teaching will be explained together withcomparative examples. Note that the present teaching is not limited toand is not restricted by the examples and the comparative examples whichwill be described below.

Preparation of Treatment Solution

Components each indicated in Composition of Treatment Solution (TABLE 1)were mixed uniformly or homogeneously, and thus treatment solutions 1 to17 were obtained.

Preparation of Water-Based Ink

Components except for water dispersions of pigments (pigment waterdispersions), which were included in Composition of Water-based Ink(TABLE 2), were mixed uniformly or homogeneously; and thus an inksolvent was obtained. Subsequently, the ink solvent was added to each ofthe pigment water dispersions, followed by being mixed uniformly. Afterthat, the obtained mixtures were each filtrated through a celluloseacetate membrane filter (pore size 3.00 μm) produced by Toyo RoshiKaisha, Ltd., and thus water-based black inks for ink-jet recording K1to K3, water-based yellow inks for ink jet recording Y1 and Y2,water-based magenta inks for ink-jet recording M1 and M2, and awater-based cyan ink for ink-jet recording Cl were obtained.

In TABLE 1:

1: Produced by KYOWA HAKKO BIO Co., Ltd.

2: Un-neutralized product of polyallylamine (weight-average molecularweight: 3000); produced by Nitto Boseki Co., Ltd.; active ingredientamount: 20% by weight; parenthesized numeral in the table indicatesactive ingredient amount.

3: Produced by Kao Corporation; parenthesized numeral in the tableindicates active ingredient amount.

4: Ethylene oxide (10 mol) adduct of acetylene diol; manufactured byNisshin Kagaku Kogyo KK.

Unit of the blending amount in the table: % by weight.

In TABLE 2:

5: Water dispersion of pigment, produced by Cabot Specialty Chemicals,Inc.; parenthesized numeral in the table indicates pigment solid contentamount.

3: Produced by Kao Corporation; parenthesized numeral in the tableindicates active ingredient amount.

4: Ethylene oxide (10 mol) adduct of acetylene diol; manufactured byNisshin Kagaku Kogyo KK.

Unit of the blending amount in the table: % by weight.

TABLE 1 Treatment solution 1 2 3 4 5 6 7 8 9 10 Composition of Lysinehydrochloride (*1) 7.00 2.00 1.00 10.00  — — — — — — Treatment Ornithinehydrochloride (*1) — — — — 7.00 1.00 — — — — solution Arginine glutamate(*1) — — — — — — 7.00 — — — (% by weight) Arginine (*1) — — — — — — —7.00 7.00 — Histidine (*1) — — — — — — — — — 1.00 Alanine (*1) — — — — —— — — — — Glycine (*1) — — — — — — — — — — Glutamic acid (*1) — — — — —— — — — — PAA (trade name)-03 (*2) — — — — — — — — — — Calcium nitratetetrahydrate — — — — — — — — — — Tetraethylammonium — — — — — — — — — —chloride Glycerol (*3) 33.10  35.50  37.40  29.00  33.50  37.50  32.50 30.00  31.80  38.20  Dipropylene glycol-n-propyl 1.00 1.00 1.00 1.001.00 1.00 1.00 1.00 1.00 1.00 ether ORFIN 0.20 0.20 0.20 0.20 0.20 0.200.20 0.20 0.20 0.20 (trade name) E1010 (*4) Malic acid — — — — — — —1.00 — — Triethanolamine — — — — — — — — — — Water balance balancebalance balance balance balance balance balance balance balanceTreatment solution 11 12 13 14 15 16 17 Composition of Lysinehydrochloride (*1) 0.50 — — — — — — Treatment Ornithine hydrochloride(*1) — — — — — — — solution Arginine glutamate (*1) — — — — — — — (% byweight) Arginine (*1) — — — — — — — Histidine (*1) — — — — — — — Alanine(*1) — 7.00 — — — — — Glycine (*1) — — 7.00 — — — — Glutamic acid (*1) —— — 7.00 — — — PAA (trade name)-03 (*2) — — — — 7.00 — — Calcium nitratetetrahydrate — — — — — 7.00 — Tetraethylammonium — — — — — — 7.00chloride Glycerol (*3) 41.50  35.50  35.50  17.00  16.00  32.00  30.00 Dipropylene glycol-n-propyl 1.00 1.00 1.00 1.00 1.00 1.00 1.00 etherORFIN 0.20 0.20 0.20 0.20 0.20 0.20 0.20 (trade name) E1010 (*4) Malicacid — — — — — — — Triethanolamine — — — 11.00  — — — Water balancebalance balance balance balance balance balance

TABLE 2 Water-based ink K1 K2 K3 Y1 Y2 M1 M2 C1 Composition of CAB-O-JET4.00 — — — — — — — water-based ink (trade name) 200 (*5) (% by weight)CAB-O-JET — 4.00 — — — — — — (trade name) 300 (*5) CAB-O-JET — — 4.00 —— — — — (trade name) 400 (*5) CAB-O-JET — — — 3.00 — — — — (trade name)270Y (*5) CAB-O-JET — — — — 3.00 — — — (trade name) 470Y (*5) CAB-O-JET— — — — — 4.00 — — (trade name) 260M (*5) CAB-O-JET — — — — — — 4.50 —(trade name) 460M (*5) CAB-O-JET — — — — — — — 2.50 (trade name) 450C(*5) Glycerol (*3) 26.00  25.50  26.50  28.50  28.50  21.50  26.00 30.00  Dipropylene glycol-n- 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00propyl ether ORFIN (trade name) 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20E1010 (*4) Water balance balance balance balance balance balance balancebalance

Examples 1-29 and Comparative Examples 9-22

As shown in TABLE 3, the treatment solutions 1-17 were used incombination with the water-based black inks for ink-jet recording K1 toK3, the water-based yellow inks for ink jet recording Y1 and Y2, thewater-based magenta inks for ink jet recording M1 and M2, and thewater-based cyan ink for ink-jet recording Cl to perform recording; and(a) evaluation of the optical density (OD value) of the recorded matter,(b) evaluation of highlighter-resisting property, (c) storage stabilityof the treatment solution, (d) jetting stability of the treatmentsolution and (e) overall evaluation were performed in the followingmanner. Note that samples used for (a) the evaluation of the opticaldensity (OD value) of the recorded matter and (b) the evaluation ofhighlighter-resisting property were prepared in the following manner.

Preparation of Evaluation Samples

The treatment solutions 1-17 used in Examples 1-29 and Comparativeexamples 9-22 were each spread uniformly on a plain recording papersheet with a bar coater (Bar Coater, Rod No. 0 produced by Yasuda SeikiSeisakusho, Ltd.). The coating amount of the treatment solution was 0.9mg/cm³. Next, a digital multifunction machine DCP-595CN provided with anink jet printer produced by Brother Industries, Ltd. was used to recorda single-color patch with the water-based inks for ink jet recording ofExamples 1-29 and Comparative Examples 9-22 on the recording plain papersheets, on each of which one of the treatment solutions had been spread,at a resolution of 600 dpi×600 dpi, and evaluation samples wereprepared. Paper sheets used as the plain recording paper sheets were “MyPaper” (plain paper sheet 1) produced by Ricoh Company, Ltd.; “ClassicWhite” (plain paper sheet 2) produced by Steinbeis Temming Papier; and“Office Paper” (plain paper sheet 3) produced by Fujitsu CoWor Co., Ltd.

(a) Evaluation of Optical Density (OD Value) of Recorded Matter

After one day from the sample preparation, the optical density (ODvalue) of each of the evaluation samples at five locations (fiveportions) of each evaluation sample was measured by using aspectrophotometric colorimetry meter SpectroEye (light source: D₅₀;field: 2 degrees; density: ANSI T; reference white: Abs) produced byGretag Macbeth, and the average value of the optical density (OD value)of the respective recorded matters in the plain paper sheets 1 to 3 wasobtained (hereinafter referred to also as “average value of the opticaldensity”). The average value of the optical density of each of Examples1-29 and Comparative Examples 9-22 was compared with a referencethereof, and the evaluations was made for each of Examples 1-29 andComparative Examples 9-22 based on the following evaluation criterion.The reference, with which each of Examples 1-29 and Comparative Examples9-22 was compared (comparison objective) is a recorded matter on whichthe recording has been performed with the same water-based ink as thatused in each of Examples 1-29 and Comparative Examples 9-22 but withoutusing the treatment solution, and is any one of recorded mattersprepared in Comparative Examples 1-8 which will be described later on.Specifically, the reference for Examples 1-3 and 12-14, ComparativeExamples 9, 11, 13, 15, 17, 19 and 21 is Comparative Example 1; and thereference for Examples 6 and 18, Comparative Examples 10, 12, 14, 16,18, 20 and 22 is Comparative Example 4. Similarly, the reference forExamples 4, 15, 21, 25, 28 and 29 is Comparative Example 2; thereference for Examples 5 and 16 is Comparative Example 3; the referencefor Examples 7, 8, 19, 23 and 26 is Comparative Example 5; the referencefor Examples 9, 20, 24 and 27 is Comparative Example 6; the referencefor Examples 10 and 17 is Comparative Example 7; the reference forExamples 11 and 22 is Comparative Example 8. By performing suchcomparisons with the references, it was possible to evaluate as to theoptical density of each of the recorded matters was increased to whichextent due to the usage of the treatment solution.

Evaluation Criterion of Optical Density (OD Value) of Recorded Matter

AAA: The average value of the optical density was increased by not lessthan 0.15, as compared with the reference.

AA: The average value of the optical density was increased by not lessthan 0.08 to less than 0.15, as compared with the reference.

A: The average value of the optical density was increased by not lessthan 0.04 to less than 0.08, as compared with the reference.

B: The average value of the optical density was increased by not lessthan 0.02 to less than 0.04, as compared with the reference.

C: The average value of the optical density was increased by less than0.02, as compared with the reference.

(b) Evaluation of Highlighter-Resisting Property

After one day from the sample preparation, a text portion (letterportion) of each of the evaluation samples was traced by ahighlighter-pen with a fluorescent color twice at the load of 1N.Blurring of the text and dirtiness at the tip of the pen were visuallyobserved, and evaluations were made for the evaluation samples based onthe following evaluation criterion.

Evaluation Criterion of Highlighter-Resisting Property

A: Flowing of the ink from the letter was hardly observed.

C: Flowing of the ink from the letter was observed.

(c) Evaluation of Storage Stability of the Treatment Solution

The treatment solution of each of Examples 1-29 and Comparative Examples9-22 was stored for two weeks at a temperature of 60 degrees Celsius.After the storage, the treatment solution of each of Examples 1-29 andComparative Examples 9-22 was cooled to the normal temperature (25degrees Celsius), and evaluations were made for the treatment solutionsbased on the following evaluation criterion.

Evaluation Criterion of Storage Stability of the Treatment Solution

A: The treatment solution hardly underwent color-change (yellowed) ascompared with before the storage.

C: The treatment solution underwent color-change (yellowed) as comparedwith before the storage.

(d) Evaluation of Jetting Stability of the Treatment Solution

Each of the treatment solutions of Examples 1-29 and Comparativeexamples 9-22 was used to perform continuous discharge of hundredmillion dots (about 30,000 sheets of paper) on “Office Paper W”(recording paper) produced by Fujitsu CoWor Co Ltd, with the digitalmultifunction machine DCP-595CN provided with the ink jet printer. Theresults of the continuous discharge were evaluated in accordance withthe following evaluation criterion. Note that the term “un-discharge(non-discharge)” indicates such a state that the nozzles of the ink-jethead are clogged and the treatment solution is not discharged from thenozzles; and that the term “discharge-bending (discharge-deflection)”indicates such a state that a part of portion of the nozzles of theink-jet head are clogged, and the treatment solution is not dischargedperpendicularly to the recording paper, but is discharged obliquely withrespect to the recording paper.

Evaluation Criterion for Jetting Stability of the Treatment Solution

AA: Un-discharge and discharge-bending did not occur at all during thecontinuous discharge.

A: Although un-discharge or discharge-bending slightly occurred in thecontinuous discharge, the un-discharge or discharge-bending wasrecovered by performing purge not more than five (5) times.

C: Un-discharge and discharge-bending occurred many times in thecontinuous discharge, and both of the un-discharge and discharge-bendingdid not recover in a short period of time.

(e) Overall Evaluation

Overall evaluation was performed in accordance with the followingevaluation criterion based on the results of (a) to (d) described above.

Evaluation Criterion for Overall Evaluation

G: There was no “B” or “C” in the results of evaluations (a) to (d).

NG: There was “B” or “C” in any of the results of evaluations (a) to(d).

Comparative Examples 1-8

As comparative examples 1-8, the water-based black inks for ink jetrecording K1 to K3, the water-based yellow inks for ink jet recording Y1and Y2, the water-based magenta inks for ink jet recording M1 and M2,and the water-based cyan ink for ink-jet recording C1 were used singlywithout being combined with the treatment solution, and (a) theevaluation of the optical density (OD value) of the recorded matter, (b)the evaluation of highlighter-resisting property and (e) the overallevaluation were performed in the above-described manner. Note that in(a) the evaluation of the optical density (OD value) of the recordedmatter, Comparative Examples 1-8 themselves are the references thereofrespectively. Accordingly, the evaluation of “C” was given forComparative Examples 1-8 since the average value of the optical densitywas not increased from the reference.

The evaluation results for Examples 1-29 and Comparative examples 1-22are shown in TABLE 3.

TABLE 3 Evaluations Highlighter- Storage stability Jetting stabilityTreatment Water-based Optical density resisting of treatment oftreatment Overall solution ink (OD value) property solution solutionevaluation EX. 1 1 K2 AA A A AA G EX. 2 2 K2 AA A A AA G EX. 3 3 K2 A AA AA G EX. 4 1 K3 AA A A AA G EX. 5 1 K1 A A A AA G EX. 6 1 M1 A A A AAG EX. 7 1 M2 AA A A AA G EX. 8 3 M2 A A A AA G EX. 9 1 C1 AA A A AA GEX. 10 1 Y1 A A A AA G EX. 11 1 Y2 A A A AA G EX. 12 4 K2 AA A A A G EX.13 5 K2 AA A A AA G EX. 14 6 K2 A A A AA G EX. 15 5 K3 AA A A AA G EX.16 5 K1 A A A AA G EX. 17 5 Y1 A A A AA G EX. 18 5 M1 A A A AA G EX. 195 M2 AA A A AA G EX. 20 5 C1 AA A A AA G EX. 21 7 K3 AA A A AA G EX. 227 Y2 A A A AA G EX. 23 7 M2 AA A A AA G EX. 24 7 C1 AA A A AA G EX. 25 8K3 AA A A AA G EX. 26 8 M2 AA A A AA G EX. 27 8 C1 AA A A AA G EX. 28 9K3 AA A A AA G EX. 29 10 K3 A A A AA G COM. EX. 1 None K2 C A — — NGCOM. EX. 2 None K3 C A — — NG COM. EX. 3 None K1 C A — — NG COM. EX. 4None M1 C A — — NG COM. EX. 5 None M2 C A — — NG COM. EX. 6 None C1 C A— — NG COM. EX. 7 None Y1 C A — — NG COM. EX. 8 None Y2 C A — — NG COM.EX. 9 11 K2 B A A AA NG COM. EX. 10 11 M1 B A A AA NG COM. EX. 11 12 K2C A A AA NG COM. EX. 12 12 M1 C A A AA NG COM. EX. 13 13 K2 C A A AA NGCOM. EX. 14 13 M1 C A A AA NG COM. EX. 15 14 K2 C A A AA NG COM. EX. 1614 M1 C A A AA NG COM. EX. 17 15 K2 AA A C C NG COM. EX. 18 15 M1 AA A CC NG COM. EX. 19 16 K2 AA C A AA NG COM. EX. 20 16 M1 AA C A AA NG COM.EX. 21 17 K2 A C A A NG COM. EX. 22 17 M1 A C A A NG

As shown in TABLE 3, in each of Examples 1-29 using one of the treatmentsolutions 1-10 containing the basic amino acid in an amount of not lessthan 1% by weight, the evaluation of optical density (OD value) of therecorded matter, the evaluation of highlighter-resisting property, andthe evaluation of storage stability of the treatment solution had allsatisfactory results. In particular, in each of Examples 1, 2, 4, 7, 9,12, 13, 15, 19-21 and 23-28 using the treatment solution containing thebasic amino acid in a blending amount of not less than 2% by weight, theoptical density (OD value) of the recorded matter was further improved.Furthermore, Examples 1-29 also had a satisfactory result of jettingstability of the treatment solution. Moreover, in each of Examples 1, 2,4, 7, 9, 13, 15, 19-21 and 23-28 using the treatment solution containingthe basic amino acid in a blending amount in a range of 2% by weight to7% by weight, the optical density (OD value) of the recorded matter wasfurther improved and the jetting stability of the treatment solution hada satisfactory result.

On the other hand, as shown in TABLE 3, in Comparative Examples 1-8 inwhich the treatment solution was not used, the evaluation result of theoptical density (OD value) of the recorded matter was not satisfactory.Further, also in Comparative Examples 9 and 10 each using the treatmentsolution 11 containing the basic amino acid in a blending amount of 0.5%by weight, the evaluation result of the optical density (OD value) ofthe recorded matter was not satisfactory. Furthermore, also inComparative Examples 11-16 each using one of the treatment solutions12-14 containing neutral amino acid or acidic amino acid rather than thebasic amino acid, the evaluation result of the optical density (ODvalue) of the recorded matter was not satisfactory. Moreover, inComparative Examples 17 and 18 each using the treatment solution 15containing un-neutralized product of polyallylamine rather than thebasic amino acid, the evaluation results of the storage stability of thetreatment solution and the jetting stability of the treatment solutionwere not satisfactory. Further, in Comparative Examples 19-22 each usingone of the treatment solutions 16 and 17 containing calcium nitratetetrahydrate and tetraethylammonium chloride respectively, rather thanthe basic amino acid, the evaluation result of the highlighter-resistingproperty was not satisfactory.

As described above, the treatment solution of the present teaching isexcellent in all of the optical density (OD value) of a recorded matter,the highlighter-resisting property and the storage stability, and alsohas excellent jetting stability. The usage of the treatment solution ofthe present teaching is not particularly limited; and the treatmentsolution is widely applicable to a variety of kinds of ink-jetrecording.

1. A treatment solution for ink-jet recording, comprising: water; andbasic amino acid or a salt thereof which is contained in the treatmentsolution in a amount of not less than 1% by weight.
 2. The treatmentsolution according to claim 1, wherein the basic amino acid is selectedfrom the group consisting of lysine, arginine, histidine and ornithine.3. The treatment solution according to claim 1, wherein the basic aminoacid is contained in the treatment solution in an amount of not lessthan 2% by weight.
 4. The treatment solution according to claim 3,wherein the basic amino acid is contained in the treatment solution inan amount ranging from 2% by weight to 7% by weight.
 5. A water-basedink set for ink jet recording, comprising: a water-based ink for ink jetrecording containing a colorant, water and a water-soluble organicsolvent; and the treatment solution as defined in claim
 1. 6. Thewater-based ink set for ink-jet recording according to claim 5, whereinthe colorant is a pigment.
 7. The water-based ink set for ink-jetrecording according to claim 5, wherein the basic amino acid is selectedfrom the group consisting of lysine, arginine, histidine and ornithine.8. The water-based ink set for ink-jet recording according to claim 5,wherein the basic amino acid is contained in the treatment solution inan amount of not less than 2% by weight.
 9. The water-based ink set forink-jet recording according to claim 5, wherein the basic amino acid iscontained in the treatment solution in an amount ranging from 2% byweight to 7% by weight.
 10. An ink jet recording method for performingrecording on a recording medium, the method comprising: applying, to therecording medium, the treatment solution of the water-based ink set forink jet recording as defined in claim 5; and discharging, to therecording medium, the water-based ink of the water-based ink set forink-jet recording.
 11. The ink-jet recording method according to claim10, wherein the water-based ink is discharged to the recording mediumafter the applying of the treatment solution to the recording medium.12. The ink-jet recording method according to claim 10, wherein thetreatment solution is applied to the recording medium by discharging thetreatment solution to the recording medium.
 13. An ink jet recordingapparatus which performs recording on a recording medium, the apparatuscomprising: an ink-set accommodating section which accommodates thewater-based ink set for ink-jet recording as defined in claim 5 therein;a treatment solution applying mechanism which applies, to the recordingmedium, the treatment solution of the water-based ink set for ink-jetrecording; and an ink discharge mechanism which discharges, to therecording medium, the water-based ink of the water-based ink set. 14.The ink-jet recording apparatus according to claim 13, wherein thetreatment solution applying mechanism is a treatment solution dischargemechanism which discharges the treatment solution to the recordingmedium.